If it was able to make 300 right after takeoff on 2 engines and the destination was LA it's possible it was a ferry. I can't imagine making that altitude with any payload so question whether pax were involved. I agree it's necessary to continue on your flight plan until the issue of where to land is resolved with the company. In fact, the last engine I shut down, that's precisely what we did while the F/O worked a phone patch with the company.